The UK defence secretary said he was making no contingency plans for moving Trident out of Scotland in the event of its people voting yes to independence.

Philip Hammond believed voters would say no in the 2014 referendum.

The minister was in Scotland to announce a £350m investment in plans to replace nuclear weapons system Trident, based at Faslane on the Clyde.

First Minister Alex Salmond has pledged that in an independent Scotland nuclear weapons would be made illegal.

He said that if an SNP government was elected post-independence the new constitution would outlaw Trident and other such weapons.

Mr Hammond was visiting the Faslane Naval base where he detailed the new investment plan which he claims will create 1,200 jobs across the UK.

Experts say replacing the current Trident system will cost up to £20bn, although a decision on whether to proceed with it has effectively been pushed back to 2016, until after the next election, scheduled for May 2015.

Analysis

By James CookScotland Correspondent, BBC News

"It's a beautiful setting for a terrible weapon.

"Framed by the reds and russets of autumn, HMS Victorious lies at berth on the banks of the Clyde.

"Only the occasional burst of machine-gun fire from a training range disturbs the air.

"The Vanguard class submarine is one of four which host the UK's nuclear weapons system of Trident missiles.

"For decades Faslane, this place of contrasts, has attracted sharply differing claims about employment, defence and morality.

"That debate is now intensifying for two reasons. The Vanguard craft are approaching the end of their working life, in the 2020s. And Scotland is approaching a referendum on independence, in autumn 2014.

"The Ministry of Defence says it's responsible and sensible to plan for a replacement.

"Opponents, including the Scottish National Party, say it's arrogant and immoral. Faslane is sure to remain a political battleground for years to come."

That will also be two years after the Scottish independence referendum.

Speaking on BBC Radio Scotland's Good Morning Scotland programme, Mr Hammond said: "The UK government is not planning around the possibility of a yes vote in the referendum. We are very confident that the Scottish people will recognise the value of remaining within the UK and choose to do so.

"We are not making contingency planning for a yes vote in the referendum. Were there to be a yes vote then all sorts of things would need to be reviewed, but we are not making any contingency planning for that.

"You can be confident that around a capability as important to the UK's defence as our strategic nuclear deterrent we will have all sorts of contingency plans for maintaining the deterrent in place in all sorts of circumstances - that is sound, good operational planning."

Mr Salmond had suggested on the BBC's Andrew Marr programme a week ago that the the UK government could either relocate Trident to another part of the rest of the UK or alternatively use nuclear facilities in America or France.

He added: "Or, alternative of course, they could decide on what would be a much better policy which would be to decommission the weapons system. But that would be a matter for the London government and the SNP proposal would be to write that into the constitution of the state. So that would make the possession of nuclear weapons illegal in Scotland."

Mr Hammond said that the Faslane complex was the largest employment site in Scotland with more than 6,500 jobs underpinning the local economy.

Media captionPhilip Hammond: "It is so irresponsible to play games with a strategic deterrent like the UK nuclear deterrent."

The UK government plans to have all Royal Navy submarines based at Faslane by 2017 which promises to create a workforce of more than 8,000 by 2022.

However, the SNP government has insisted that Trident currently supports about 500 jobs.

Mr Hammond told BBC Scotland: "The plans that we have now will take us well into the second half of this century.

"You can't say with any certainty today who will be threatening us in 20, 30, 40 or 50 years' time.

"That is why it is so irresponsible to play games with a strategic deterrent like the UK nuclear deterrent.

"It is there to protect our nation, all the people of the UK, against any threat, whether it comes from another major power, or whether it comes from a rogue nuclear state, or whether it comes from a terrorist group."

'Waste of money'

Scottish Deputy First Minister Nicola Sturgeon attacked the UK government for "dumping" weapons of mass destruction on Scotland, and said there was cross-party support for scrapping the renewal of Trident in the Scottish Parliament.

She said: "The vast amount of taxpayers' cash squandered by the UK government on designing the new Trident system during a period of austerity and cuts to services and benefits by the Tory-led coalition is a staggering waste of money.

"The obscene amount ploughed into upgrading and maintaining Trident illustrates the independence dividend, and how with the powers of an independent parliament we could spend Scotland's share of Trident spending on key public services.

"The Scottish Parliament has voted clearly, across parties, against Trident renewal and most Scots want the parliament to have the powers to get rid of Trident."

Last week, the House of Commons Scottish Affairs Committee urged the UK and Scottish governments to reach a deal on nuclear weapons before the Scottish referendum.